"Flooded" tunnels aren't! ...

It was once a mystery how soil-dwelling animals could keep from drowning during temporary flooding. We used this sand-filled tunnel box to demonstrate how water goes AROUND a cavity instead of THROUGH it. If the soil particles are small (as with clay) it takes a long time for water to be absorbed and percolate through the soil.
 
Due to the capillary attraction of soil particles, water percolating through soil cannot enter open animal tunnels. Water can only flow into these open cavities if there is an opening at the ground surface or the water table rises from below.